1. Field of the Invention
This invention relates to a light source, and more particularly to a search light that uses multiple light sources to create a single concentrated beam of light as a menorah configuration of light sources.
2. Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98
Collimators are well known in the optical arts, and typically include a plurality of lens or reflectors that act upon light to emit nearly parallel rays. Such collimators include searchlights, headlamps and light projectors. A typical example of a light projector designed to emit a collimated beam can be found in U.S. Pat. No. 5,918,968, issued to Choi, which provides a parabolic reflector for converting light emitted from a lamp to parallel rays, a biconvex lens for collimating both direct and reflected light from the light source, a combination lens having a first lens and a second lens for focusing the collimated light from the biconvex lens to a focal point, and an image lens located beyond the focal point for converting the light focused at the focal point into a parallel beam.
U.S. Pat. No. 6,827,475, issued to Vetorino et al., combines a plurality of lens and reflectors to collimate light that includes a conical reflector disposed about the base of a light emitting diode (LED) and a lens specially designed to focus the collected light into a nearly collimated beam. The lens have opposite, substantially elliptical surfaces that collect and collimate the rapidly diverging light from the LED and the reflector. Vetorino et al., however, do not provide for the compression of the collimated beam.
It is also known in the art that the illuminance Lx of a light stream from a light source located perpendicular to an area illuminates that area according to the following relationship: Lx=Lm/m.sup.2. For example, one Lx of illuminance is equal to one Lm of luminous flux for an illuminated surface measuring one square meter in area, and with the light source arranged perpendicular to the surface. In another example, if the luminous flux is equal to 1,000 Lm and the uniformly illuminated surface is one square meter, then the illuminance of that area equals 1,000 Lx. Thus, in order to measure the luminous flux in a uniformly illuminated area of 1.0 square meters, a Lux Meter may be placed anywhere in the illuminated area.
Some prior art producers of light sources, e.g., prior art flashlights utilizing light emitting diodes (LED) claim values of luminous flux (Lm) which in some instances appear higher than the maximum value that can be emitted by the light emitting diode in all directions. Such claims do not account for the uniformity of illuminance (Lx) of an illuminated area where the measurement was taken. Experimentally, the illuminance of two prior art LED's, have been measured and compared to their maximum luminous flux. Two prior art flashlights were chosen for the measurement: (1) ND HB F5, 6V, 2CR 123, 107 Lm Cree LED (hereinafter “HB F5”), and (2) NH HB VIGOUR, 6V, 2CR 123, 107 Lm Cree LED (hereinafter “HB VIGOUR”). Each flashlight having substantially identical electrical specifications, but different optical schematics. The HB F5 appears to utilize an optical schematic that allows for concentrated light emission with uniform luminous flux through the light stream and +/−2.5° angle of dispersion relative to the optical axis. The HB VIGOUR utilizes a focusing output lens system.
Other light sources include flashlights which typically comprise a light source, a reflector located behind the light source, a lens or glass in front of the reflector, and a power supply. The reflector and the lens are intended to collect light from the source and collimate or focus the light into a desired beam. Such light sources are often portable, and generally produce a diverging beam of light whereby the brightness varies across the beam. Typically, the light beam is brightness at its center, and drops off dramatically at its peripheral edge. Examples of such prior art lights may be found in U.S. Pat. Nos. 1,823,762, 2,228,078, 4,286,311, and 4,527,223.
An important advantage of the present invention is the provision of a light device where the light beam is minimally divergent or compressed along the optical axis, thereby allowing for increased intensity over an illumination range of interest.
A number of patents and or publications have been made to address these issues. Exemplary examples of patents and or publication that try to address this/these problem(s) are identified and discussed below.